<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>

</head>

<body>

  <div id="app">

  </div>

  <!-- 增加React的依赖 -->
  <script src="https://unpkg.com/react@16/umd/react.development.js" crossorigin></script>
  <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js" crossorigin></script>
  <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>


  <!-- 开始开发-->
  <script type="text/babel">
    //封装App组件
    class App extends React.Component {

      //定义属性
      constructor() {
        super();
        // this.message = "Hello World"
        this.state = {
          message: "Hello World",
        }

      }

      render() {
        return (
          <div>
            <h2>{this.state.message}</h2>
            <button onClick={this.btnClick.bind(this)}>改变文本</button>
          </div>
        )
      }
      btnClick() {
        this.setState({
          message: "Hello React",
        })

      }
    }

    //渲染组件
    ReactDOM.render(<App />, document.getElementById("app"))

  </script>
</body>

</html>